Along with the development of communication techniques, the service triggered by off-hook is used in more and more applications. For example, if a user has registered an instant hot line, a Soft Switch (SS) will automatically dial the hotline number registered by the user to implement the service triggered by off-hook after the user is off-hook. If the user is in a fee-due status, the SS will play for the user a fee-due prompting tone to remind the user of paying for the call timely after the user is off-hook. If there is a shortage of the balance of the calling prepaid account, the SS will play for the user a prompting tone to remind the user of recharging timely after the user is off-hook.
In a Next Generation Network (NGN), since the user generally subscribes to a service on the SS, the information of a service triggered by off-hook which the user has subscribed to is stored in the SS, in this way, the implementation of the service triggered by off-hook is controlled by the SS.
In an IP Multimedia Subsystem (IMS), since the user generally subscribes to a service on an Access Gateway Control Function (AGCF), the information of the service triggered by off-hook which the user has subscribed to is stored in the AGCF. Thus, the AGCF controls the implementation of the service triggered by off-hook.
At present, in the NGN or the IMS network, the service triggered by off-hook is independently implemented by the SS or the AGCF, and the user has to subscribe to the service triggered by off-hook in advance on the SS or the AGCF, so it is impossible to separate the specific service implementation from the service control. Along with the development of communication techniques, an Application Server (AS) for implementing the service control is sure to implement more and more service control functions. Increasing services require to be subscribed on the AS by the users and it has become a trend of the current development of communication techniques to control the implementation of various services by the AS.
However, the information of the service triggered by off-hook which is subscribed by the user can not be transmitted between the existing AS and the SS or the AGCF, as a result, the SS or the AGCF may not acquire the information of the service triggered by off-hook which is subscribed by the user from the AS if the service triggered by off-hook is subscribed on the AS, which makes it impossible to implement the service triggered by off-hook.